US endocrinologist Robert Lustig is on a crusade against sugar. He talks to Balaji Ravichandran about why he believes we are getting fatter and how he hopes to start tackling the sugar industry

A man who declares that sugar is a toxin in the same league as cocaine and alcohol, and one that must be regulated in the same manner as tobacco, is apt to draw public attention. But Robert Lustig, professor of clinical paediatrics at the University of California, San Fransisco, is not camera shy. Indeed, he revels in the attention, even when it is not always flattering. Where other academics might feel uncomfortable, he exploits his fame to full effect. For example, at a recent symposium in London he argued that sugar was an addictive and dangerous substance, singularly responsible for the soaring rates of obesity and diabetes around the world. He began his speech with a quotation from Gandhi and concluded by declaring a war against the sugar industry. The audience responded with rapture and enthusiasm.

Lustig, a paediatric endocrinologist specialising in neuroendocrinology, owes his fame predominantly to a lecture, posted on YouTube, entitled “Sugar: The Bitter Truth” (www.youtube.com/watch?v=dBnniua6-oM). At the time of writing, it had had more than 3.3 million views. Not bad for a 90 minute lecture, the bulk of which is devoted to complex biochemical reactions that happen in the liver. But Lustig is an engaging and passionate speaker, prone to rhetorical flourishes and dramatic pronouncements, which keeps his audience, virtual and real, interested.

Lustig believes that the advice we have received from doctors and nutritionists over the past 40 years—that, in order to lose weight and keep obesity and diabetes at bay, you must eat less and exercise more—is wrong. Although he says that the first law of thermodynamics—that energy can neither be …